fix https://github.com/sagemathinc/smc/issues/765 -- parse_bup_timestamp fails on OS X
fix https://github.com/sagemathinc/smc/issues/765 -- parse_bup_timestamp fails on OS X

DrXyzzy/smc,sagemathinc/smc,sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc